Essentially, at the moment, over-collateralized loans. Deposit $100 and borrow $90, if you pay back $95 by tomorrow you get your original $100 back. There's actually some really cool and complex financial instruments you can build by combining these and the nature of atomic transactions on the blockchain (you can take a loan and pay it back in the same transaction while using the money in other txs to get a profit, it's really weird HFT).